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Correlation between the stapes prosthesis insertion depth within the vestibule and postoperative clinical outcome
18 April 2018 (online)
The insertion of the stapes prosthesis piston within the vestibule provides the physical basis for a successful stapedotomy. The insertion depth of 0,5 mm is recommended to avoid the dislocation of the stapes prosthesis (e.g. sneezing). This measure serves as a basis for the selection of the correct length of the prosthesis. Deep intravestibular prosthesis insertion has been associated with postoperative vertigo. The objective of this research is to analyse the stapes prosthesis insertion depth and its correlative impact on clinical outcome by means of radiological examination.
Material and Methods:
We observed radiologically 47 patients with the diagnosis of otosclerosis by a flat panel tomography after a stapedotomy. Radiological evaluation included the prosthesis insertion depth within the vestibule, the length of the prosthesis, the size of vestibule and, 3 weeks postoperatively, the bone conduction threshold, vertigo and tinnitus.
Insertion depth varies between 0,3 and 1,7 mm (mean 0,86 mm). The ratio of insertion depth and the size of vestibule was between 10 and 63 (mean 33,75). A postoperative decrease of the bone conduction of 10 dB – 20 dB (mean 4 frequencies) was found in 4 cases. An overclosure was observed in 18 cases. We observed no correlation between the insertion depth, the length oft he prosthesis, the ratio of the insertion depth and the size of vestibule, postoperative bone conduction, appearance of vertigo or tinnitus.
The insertion depth of the stapes piston does not seem to have any influence on postoperative vertigo, tinnitus or decrease of the bone conduction within the mentioned boundaries.